Manufacture of carbon black



May 20, 1952 w. c. EKHOLM ET AL MANUFACTURE OF CARBON BLACK original Filed March 25, 1948 3 Sheets-Sheet l ali/wm ATTORN EYS May 20, 1952 w. c. EKHOLM ET AL 2,597,233

MANUFCTURE OF CARBON BLACK Original Filed March 23, 1948 5 Sheets-Sheet 2 N I' i-. ooAoooooooOoooooo FIG. 2

May 20, 1952 w. c. EKHOLM E-r AL 2,597,233

MANUFACTURE oF CARBON BLACK Original Filed March 23, 1948 5 Sheets-Sheet 5 FIG. 3

@Page A. /fF/Ier Patented May 20, 1952 ENCE MANUFACTURE OF CARBON BLACK Wesley C. Ekholm and George L. Heller, Monroe, La., assignors to Columbian Carbon Company, New York, N. Y., a corporation of Delaware Continuation of application Serial No. 16,586,

March 23, 1948.

1950, Serial No. 181,424

The present invention relates to the manufacture of furnace blacks and provides improved apparatus especially adapted to the vcarrying out of the process described and claimed in the Wiegand and Braendle Patent No. 2,378,055 and a special adaptation of that process described in the Wiegand and Braendle Patent No. 2,440.424. In a particularly advantageous modification thereof, the apparatus of our present invention is further especially adapted to the carrying out of the process described and claimed in our copendingrapplication.Serial No. 16.585.1iledMarch 23, 1948, as more fully described herein. The present application is a' continuation of our copending application Serial No. 16,586, also filed March 23, 1948. now abandoned.

. In accordance with the process of the said patents, a hot, high velocity violently turbulent stream of blast flame gases is generated at one end of an elongated reaction chamber by the burning of a combustible mixture of air and a fuel gas therein and a iiuid hydrocarbon. herein designated make or make gas. is forcefully injectedv as a plurality of relatively small streams into the blast flame gases as they pass through the reaction chamber in a zone near the burner end thereof so that the make gas is substantially, instantaneously mixed with the blast flame gases and is decomposed by heat absorbed therefrom to form carbon black which is separated from the furnace gases passing from the downstream end of the chamber.

6 Claims. (Cl. 23-2595) We have found that, in operations of that type,

the character. aud especially the yield of the resultant carbon black. are materially iniiuenf'e'l by the configuration and dimensions of the transverse section of the stream of blast ame gases, especially at the point of iniection of the make. and the manner in which tbe make #as is iniected into and mixed with the blast flame gases. The process of our said application provides a particularly advantageous method of effecting a rapid, uniform mixing of the make gas With the blast flame gases and constitutes an improvement in the process of the said Wiegand and Braendle patents.

More particularly. We have found that the arrangement and dimensions of the furnace chamber and auxiliary equipment for injecting the make gas into the furnace chamber and for supplying the hot blast flame gases thereto, materially affect the uniformity of the mixing of the make gas with the blast flame gases. The apparatus of the present invention is so designed and constructed as to promote a more rapid uni- This application August 25,

y 2 form mixing of the make gas with the blast fiame gases with the resultant increase in yield of carbon black'for a given quantity of hydrocarbon consumed and greater ease and nicety of control of `the characteristics of the carbon black produced.

From careful observation and tests, it appears rather unexpectedly that the streams of make gas injected radially into the stream of blast flame gas passing through the reaction chamber maintain their identity for an extremely short period of time. of the order of microseconds, despite the violently turbulent iiow conditions in the reaction chamber. It further appears that uniformity of mixing is promoted by maintaining a uniform temperature, velocity and com position of the blast ame gases throughout the transverse area of the stream, particularly in the Zone Where the make gas is injected. However, uniformly rapid mixing with resultant uniform dispersion and heating of the make gas does not appear to be obtained Where the entering make gas streams do not penetrate a sufficient distance into the stream of blast flame gases before losing their identity. It appears that, in commercial sized units, there is a danger of a core of blast gas, without its quota of intermixed make, passing through the center of the furnace and resulting in undesirable reactions and quality of product, together With loss in yield. It appears that maximum yields and optimum iineness, as reflected by color, are obtained only Where there is no such core of blast iiame gases not penetrated bv the entering streams of make gas. On the other hand, We have found that where a furnace of circular cross-section is used, yield and color may be sacrificed even though the radially entering make gas streams penetrete to the center of the circular section of the furnace chamber, due to the tendency to form a core of concentrated make gas.

Regardless of the accuracy of this explanation of our improved results, we have found that improved yields are obtained in operations of this type when carried out in a furnace chamber of substantially rectangular cross-section not exceeding about 11/2 feet in width, and advantageously of greater height. provided with a blast burner of a type adapted to generate in the chamber a turbulent Stream of hot blast ame gases of substantially uniform temperature, velocity and composition throughout the transverse section of the chamber and the hydrocarbon make is forcefully injected into the chamber in a direction across the width thereof as a plurality of streams spaced along opposite sides of the furnace wall.

Predicated upon this discovery, our present invention in its broader aspect provides apparatus of the type described, comprising an elongated furnace chamber of substantially rectangular cross-section not exceeding 11/2 feet in width and of greater height and having a blast burner positioned in one end thereof, the burner comprising a rectangular burner block substantially coextensive with the transverse area of the chamber With a plurality of burner ports uniformly spaced over the face of the burner block. The furnace is further provided with a plurality of make gas injection tubes spaced along opposite sides of the furnace chamber and equi-distant from the burner end thereof, the tubes being unrestricted at their inner ends and being directed across the width of the chamber from v opposite sides thereof, each being substantially perpendicular to the opposite wall of the chamber and being directly opposite a corresponding tube entering the chamber through the opposite wall. 'Minor deviations from the perpendicular are permissible. Advantageously, the make gas injection tubes are of 1A; to 3A; inch inside diameter and are uniformly spaced over the entire height of the chamber at 1% inches to 5 inches between centers. As previously noted, the reaction chamber should be of somewhat greater height than width. However. it should not usually eszaeed tn 6 feet in height. Rea-C- tion chambers about 4 feet high have been found particularly advantageous.

`Further.z though rectangular reaction chambers up to about 1% feet wide may be used` with advantage, in accordance with our present inventinn. as nrevinuslv noted, optimum results have been obtained in furnaces approximately 'l0 to ld inches in width. We have. obtained exceptionally advantageous results with apparatus in which the. fwrnqnn nbamher ahnrmri'mates 1 fnot; in width and 4 feet in height. provided with make gas iniection tubes of V2 inch inside diameter spaced about 2% inches between centers over the entire height of the chamber and positioned about 18 inf-nes downstream from the face of the burner block.

The invention will be further described and illustrated bv reference to the accompanying drawings which represent. conventionally and somewhat diagrammatically, a presently preferred embodiment thereof comprising three reaction chambers opening at their downstream ends into a common blending chamber. It will be understood, however, that the invention is ynot restricted to the particular arrangement shown, but contemplates apparatus comprising a single reaction chamber as well as other known means within the scope of the appended claims for generating the blast flame gases and for injecting` the make into the chamber.

Referring to the drawings, Figure 1 represents a horizontal sectional View of the apparatus;

'Figure 2 is a fragmentary, vertical, longitudinal sectional view of the upstream end of a single reaction chamber, including the blast burner and make gas injection tubes; and

Figure 3 is a vertical, transverse sectional view along the lines 3, 3 of Figure 2.

As previously noted, the unit specifically illus trated comprises three reaction chambers I, each provided at its forward end with a blast burner 2, the burner block 3 of which fits into the forward end of, and is coextensive with, the transverse area of the chamber.

Each of the chambers at its downstream end opens into the common blending chamber 4 which, in turn, leads into an elongated, cylindrical chamber 5, in which the eiiiuent from the blending chamber is cooled, as by means of water sprays 6, of which there may be a plurality spaced along the length of the chamber. The eiiiuent from the chamber 5, which comprises a gaseous suspension of the furnace black, is passed to a collecting system, not shown in the drawing, for the recovery of the-furnace black from the gases.

'I'he chambers I are substantially uniform cross-sectional throughout and, in the particular apparatus illustrated, are approximately one foot wide and four feet high.

Uniformly spaced over the face of the burner block are 39 burner ports 1, '1% inches in diameter and flared at their inner ends to a diameter of three inches, as more clearly appears in Fig'- ure 2 of the drawings. At their upstream end,

the respective burnerports are provided with metal tubes, slightly flared at their inlet end and securely heldin the burner ports'by means of metal plate 9 to which they are fastened as by welding.

The respective burner ports open at their upstream end into the wind-box I0. Air for supporting'combustion' is Aforced under super-atmospheric pressure into the upstream end of the wind-box, through air inlet II, which is connected with a blower, or the like,r not shown. Air is thus forced at high velocity through the respective burner ports.' In order to secure univform distribution Yof lthe combustion air, the wind-box is provided withV a plurality of vanes I2 and adjustable dampers I3 for directing the air flowv uniformly to highly and lower zones of the wind-box. y

Also Awithin the windfbox, there are three fuel gas manifolds, I4 supported by the feed lines I5 and carriages I6, Extendingdownstream from the respective manifolds, coaxially with theV burner ports is a plurality of tubes I1, each terminating at its downstream end in a jet or spud I8. Tubes I1 are advantageously of substantially greater length than the depth of the burner ports so that the respective burner ports may be moved forward to a position such that the spuds are at, or near, the downstream end of the burner ports without substantial interference by the manifolds with the ow of air into and through the burner ports.

The manifolds III are adapted to roll freely backward and forward over the carriages I6, equipped with flanged rollers I9, thus providing ready means for adjusting the position of the spuds with respect to the burner ports.

Each of the fuel gas manifold feed lines I5 extends to the rear through the vanes and rear wall of the wind-box through a packing gland 2l) and is connected with a supply of fuel gas, under pressure, through exible tube 2I. Advantageously, the lines I5 are calibrated just without the wind-box so that the position of the spuds with respect to the burner ports may be readily determined. Where a burner such as described is used, adjustment of blast flame conditions may be readily accomplished.

In operation, the blast burner is so regulated as to inject at high velocity through the respective burner ports a, uniform combustible mixture of fuel gas and air which is burned as it leaves the ports Within the reaction chamber fo' minggahighlyfturbulentstreamvofiblast flame such tubespo'si'tioned atldiierentdis'tanc'es Afrom and such'v arrangement is withirr the' co'n'templa.-A

tion-'of our' present' invention.

Theisiz'e and number.y of' the make gasV injection' tubes are',` likewise,V subject to some variation. In'- th'ef particular-l apparatus illustrated,

36. make' gasl injection tubes` of 1/2- inchA I.A D. are providedg- 18. on either side of. the' chamber and uniformly spaced`v over the heightv of the chamber, 21/2 inches v between centers,v as more clearly appears from Figure 3 of the drawing. The

outer endsof thesetubes are providedl with' controlvalves 2f3` and are connectedl withmake gas manifolds 24 to which the make gas is supplied under' pressure through valved-connections 25. The inner' endsl of they tubes' open into the reaction chamber without constriction.

The makeg'ias, usually'naturalgas'. is supplied t'of the system, under pressure, through conduit 26 ata'. rate controlled by' valve 211and the gas'` is', with advantage; preheated by conventionalv means, not shown inv the' drawing, to a temperatur'e ofabout 700 F. Where make 'gas enrich'- ment isi' employed, ther enriching"v oil may be injected' 'intof conduit 26 throughline 28 at' a rate controlled by valve 29. Where steam is tov be mixed with a make gasyit'may be= injected into conduit 26V through line` 30 at'- a 'rate controlledby valve 3|. From' conduit 26, theY make gas, either alone or enriched, or admix'ed with steam, or` both', is passed to manifold' 32 and, from thence, through' branch line 25 leading to the make gas' manifolds 24, as previously described. Branched lines corresponding to line 25 lead from* manifold 32 to the other reaction chambers of' the unit. The amount of make gas passed to the respective manifolds of the' several reaction chambers may'v be controlled by adjustment of the several valves 33 and valves 34 indicated in' the branch lines and, by proper adjustment of these valves in conjunction with the valves 23 in the respective make gas injection tubes, the rate of injection of make gas through the several injection tubes may bev controlled and regulated'.

The respective chambers should be lined with an appropriately highly refractory material capable of withstanding high temperatures. Such refractory materials and methods of applying them are well knownto the' art and need not be described herein.

Itis frequently desirable to vary the contact time within a given apparatus. For this purpose, one or more water sprays are provided within the blending chamber, as indicated at 35, and in the downstream end of the reaction chambers, as indicated at 36.

The transverse dimensions of the reaction chamber may be varied somewhat within rather weird-annee: urnas... 'ritsen-dim sneumfncsexceeui about 1:1/1' feet: andev is;.. with.: advantage; some-e4 whatlless: Aspreviously noted,chamber'widthsf yield or characteristics.l of the black,` usuallyi.

Further', as'.previously"note'd',' the height ofthereactionr chamber should generally not exceed 5 to 6v feet. It has' been found' that, with cham'-` bersy of" greaterheight', diflicultie's are encountered due to thermal head in thechamber.

The optimum length of' the' chamber' is subject'to considerable variation, depending-upon intended operating conditions, primarily thevel'oc-r ity of thef-mixed` gases through the'chambe'r. TheV chamber should be suiciently long' to provioleA the' necessary time* factor. atthe elevated temperature' to effect therequired reaction.

Itis generally advantageous' that the'make' gas injection tubes be of circular cross-section of about 1/2 inch in diameter and that the' t'ubes be" spaced about 21/2 inches between centers. However, the diameter of the tubes and the spacing of the tubes are subject to some variation, the opti-mum inside diameter of the tube beingv dependent upon the spacing between the tubes and the Width of the furnace chamber. The number of' and spacings between the makev gas injection tubes are, with advantage, such as to give a uniform pattern of make gas streams over theentire: height of the chamber.

Close spacing ofthe make gas injection tubes appears to promote more uniform use of 'the hot blast iiame gases by preventing excessive bypassing of the hot'iianie gases between adjacent jets of make gas, and more effective mixing` of the make gas and blast flame gases is promoted. At the same time, the increased number of make gas tubes makes possible the use of tubes of smaller diameter and facilitates thel developing of velocities necessary to effect the desired pene-'- tration of the make gas streams into the stream of blast iiame gases and provides more rapid, uniform heating as well as dispersion of the make gas.

We have found that, as the diameter ofthe make gas injection tubes approaches inch, it becomes increasingly diiiicult to effect the desired makeV gasA pattern across the reaction chamber and the optimum rate of'mixing of make gas and blast gases. We, therefore, prefer to restrict the inside diameter of the make gas tubes* to a maximum between 1/2 and 3A of an inch. However, injection tubes of 1 inch, I. D. have been used with advantage- At diameters less than about 1A; inch, the make gas streams, at acceptable operating loads, appear to become too read- .ily shattered, i. e., before adequate penetration of the blast gas stream, and a condition ensues where the make gas concentration across the width of the furnace does not reach uniformity until after the onset of cracking', which condition it is one of the objects of this invention toA avoid. Likewise, with veryV small make tubes'a coking'up and plugging of the make tubes may' becomev a serious operating problem with certain types of hydrocarbon raw material.

The invention is not restricted to the use of round make gas injection tubes. Square or somewhat flattened tubes of corresponding transverse area may be used with substantially equal advantage so longas their upstream-downstream thickness is within the range of about 1A to 3A;

inch and are so proportioned as to avoid serious coking diiiiculties and to effect mass velocity sufciently-.great to avoid the too rapid shattering just described, with resultant non-uniformity of mixing. 1

Apparatus particularly adaptable to changes in the characteristics of the product, within reasonably broad limits, has been constructed having .a reaction chamber width of about 12 inches and a height of about 4 feet and using make gas injection tubes 1/2 inch in diameter, uniformly spaced along eachside of the chamber over its entire height and about 21/2 inches between centers. However, as previously indicated, the optimum spacing of these tubes will vary somewhat with the diameters of the tubes and the mass velocities to be employed, which are, in turn, dependent upon yfurnace width. Frequently, as the diameter of the make gas tubes approaches the upper permissible limit, the spacing between centers may be increased to about 5 inches. Where -tubes of the smallestpermissible diameter are used, they may frequently be arranged as close as 1% inches between centers.

The transverse area of the reaction chamber is, with advantage, so correlated with the crosssectional area of the respective make gas injection tubes and the number of make gas injec tion tubes employed as to provide, under intended' operating conditions, a ratio of vthe mass velocity of the make gas streams to the mass velocity of the blast iiame gases within the range of 3:1 to 10:1, the optimum ratio varying somewhat with the width of the furnace. With a fur nace 12 inches in width, a correlation oi' the dimensions of the respective elements to provide ratios within the range of 5.5:1 to 9:1 at the in tended operating conditions has been found particularly advantageous.

The minimum width of the furnace chamber of our present invention is dictated vprimarily by a consideration offurnace capacity and problems related to construction and maintenance.

The capacity. oi a furnace is, of course, largely dependent upon its cross-sectional area, since the volume and rate of i'iow of the blast flame gases must be sufficient to effect the necessary turbulence and the ratio of make gas to blast name gases must be kept within a rather well defined range. Further, construction and maintenance costs and difculties are multiplied where the furnace width is less than about 10 to l2 inches. Consequently, furnace widths less than about 10 inches are usually not desirable.

As previously noted, an important aspect of the apparatus of the present invention is its ability-to generate a stream of blast name gases of uniform temperature, composition, and linear velocity over its entire transverse area. This is,

with advantage, eiected by the use of a blastV It will be understood, of course, that Where the apparatus comprisesa single reaction chamber, the reaction chamber may be connected at its downstream end directly with the cooling chamber, the blending chamber being omitted.

The apparatus of our present invention has been found to be particularly effective in operations of the type described in which the make gas is enriched .by a normally liquid mineral oill fraction, as more fully described in our previously noted copending application.

We claim:

1. Apparatus of the type described comprising an elongated reaction chamber of substantial rectangular cross-section not exceeding 1% feet in Width and of a greater height than width, a blast burner positioned at one end thereof and comprising a rectangular burner block substantially coextensive with the transverse area of the chamber and provided with a plurality of burner ports uniformly spaced over the entire face of the burner block, a plurality of make gas injection tubes vertically spaced along opposite sides of the chamber, near and equi-distant from the burner end thereof, the tubes being unconstricted at their inner ends and being directed across the width of the chamber, each being substantially perpendicular to the opposite side Wall of the chamber and each being directly opposite a cor-v responding tube entering the chamber throughthe opposite side wall. Y

2. The apparatus of claim 1 in which the height of the reaction chamber does not exceed 5 to 6 feet.

3. rIhe apparatus of claim 1 in which the reaction chamber width is 1 foot, the reaction chamber height is 4 feet and the make gas in' jection tubes are 1/ inch inside diameter, are uniformly spaced about 21/2 inches between centers over the entire height on opposite sides of the chamber and are positioned about 18 inches downstream from` the face of the burner block.

4. The apparatus of claim 1 in which the aggregate sectional area of the blast burner ports approximates 25% of the transverse area of the furnace chamber.

5. The apparatus of claim 1 in which the make gas injection tubes have an inside diameter of 1A; inch to 3A inch and are uniformly spaced over the entire height of the opposite side walls of the chamber at ll/z inches to 5 inches between centers.

6. The apparatus of claim 5 in which the reaction chamber is 12 to 14 inches wide and about 4 feet in height.

v WESLEY C- EKHOLM.

GEORGE L. HELLER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,378,055 Wiegand et al 1 June 12, 1945 2,440,423 Wiegand et al Apr. 27, 1943 2,440,424 Wiegand et al Apr. 27, 1948 

1. APPARATUS OF THE TYPE DESCRIBED COMPRISING AN ELONGATED REACTION CHAMBER OF SUBSTANTIAL RECTANGULAR CROSS-SECTION NOT EXCEEDING 1 1/2 FEET IN WIDTH AND OF A GREATER HEIGHT THAN WIDTH, A BLAST BURNER POSITIONED AT ONE END THEREOF AND COMPRISING A RECTANGULAR BURNER BLOCK SUBSTANTIALLY COEXTENSIVE WITH THE TRANSVERSE AREA OF THE CHAMBER AND PROVIDED WITH A PLURALITY OF BURNER PORTS UNIFORMLY SPACED OVER THE ENTIRE FACE OF THE BURNER BLOCK, A PLURALITY OF MAKE GAS INJECTION TUBES VERTICALLY SPACED ALONG OPPOSITE SIDES OF THE CHAMBER, NEAR AND EQUI-DISTANT FROM THE BURNER END THEREOF, THE TUBES BEING UNCONSTRICTED AT THEIR INNER ENDS AND BEING DIRECTED ACROSS THE WIDTH OF THE CHAMBER, EACH BEING SUBSTANTIALLY PERPENDICULAR TO THE OPPOSITE SIDE WALL OF THE CHAMBER AND EACH BEING DIRECTLY OPPOSITE A CORRESPONDING TUBE ENTERING THE CHAMBER THROUGH THE OPPOSITE SIDE WALL. 